The absolute rates of radiative and of nonradiative decay from three vibronic levels in isolated 1B2u benzene molecules
✍ Scribed by W.R. Ware; B.K. Selinger; C.S. Parmenter; M.W. Schuyler
- Publisher
- Elsevier Science
- Year
- 1970
- Tongue
- English
- Weight
- 262 KB
- Volume
- 6
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Absolute rate constants for radiative and for nonradiative decay from three single vibronic levels of isolated 1B2u benzene molecules are derived from experimental data. Both rate constants show sensitivity to the' vibrational state of the excited molecule. Their correspondence with the theory of vibronitally induced radiative transitions and with the theory of nonradlative.transitions in large molecules is discussed. Preceding communications report the fluorescence lifetimes [I] 7 and the quantum yields [3] associated with the decay of isolated benzene molecules-from three different vibronic levels of the lB2" state, Combination of those data now provides-en explfcit experimental determination cf the separate rate constants for radiative and nonradiative decay from several specific vibronic states of a large isolated molecule. The constants are derived by classifying the decay of an isolated 1~~2~ benzene molecule into two components. One is characterized by a rate constant k, for radiative decay and the other by the constanf knr for the sum of all nonradiative processes destroying the excited electronic state. The_experimentally measured fluorescence lifetime is thus r = (/++/z,,)-1 and the fluorescence yield is Qf = &,A&, +knr) = T&.. From these-equations, tne data [l, 31 provide % Contribution No. 1807 from the Chemical Laboratories'of Indiana University. Supported by the National Science Foundation &ants GP 7813 (University of Minnesota) and GP 8451 (Indiana University).